Generally speaking, a greenhouse is a building constructed for the practice of indoor horticulture or agriculture. Traditionally, the walls and roofs of greenhouses have been constructed of glass or similar transparent material such as transparent plastic panels. This permits sunlight to directly illuminate plants, and permit them to grow. Systems have been proposed, for instance as shown in U.S. Pat. No. 5,655,335 to allow the roof of a traditionally constructed transparent greenhouse to open to permit the plants being grown therein to become hardier, thereby increasing the success rate of transplants from the greenhouse to a natural environment. In U.S. Pat. No. 5,655,335, longitudinally extending roof panels are paired together in v-shaped pairs that extend the length or width of a greenhouse. Each arm of the ‘V’ slantingly abuts the ‘V’ next to it, to define a series of peaks running the length or width of the greenhouse. Each ‘V’ shaped pair of panels is hinged together at the base of the ‘V’ and provided with mechanical means to draw the arms of the ‘V’ inward. It will be understood, then, that when one or more V shaped pairs is closed up in this way, the roof will be opened, and the natural atmosphere permitted to circulate in the open greenhouse.
It is, moreover, known to use a plurality of inflatable tubes, arranged parallel to each other to construct an insulating partition in a greenhouse. In U.S. Pat. No. 4,290,242 (Gregory), inflatable clear polyethylene tubes are arranged in longitudinal lines in a greenhouse to provide an insulating layer. The tubes are inflated to lean against each other and provide a continuous insulating ceiling structure when there is no sunlight, and deflated to hang vertically and provide passages between the tubes when the sun is shining.
A similar system is shown in U.S. Pat. No. 4,352,259 (Smith et al.), which also provides that the ends of the longitudinally extending tubes are mounted on racks, whereby the tubes may be drawn to the side of the greenhouse. Other patents that show the use of insulating structures made up of parallel inflatable tubes can be seen in U.S. Pat. No. 4,301,626 (Davis et al.), U.S. Pat. No. 600,171 (Davis) and U.S. Pat. No. 6,442,903 (Herbert).